I name them well enough to tell them apart.
Most of my pistols are 1911s. Johnny's Kimber, Dru's Kimber (former owners), the compact, the polymer, the para, the .22, etc.
I simply call my Glock "The 19" or "The Beater."
My ARs are named by caliber. The .22, 9, 5.56, and .45.
My cars are named in a similar fashion. Although I often call my wife's escort "The GoKart" (I drive a caprice or F150) and my project car is commonly referred to as "My Mistress."
I am seriously considering naming my favorite gun, but a) I haven't decided which one is my favorite and b) I haven't yet determined if it's male or female.
Depends. I never met a guy named Karen so I'm assuming you're a lady. If the pistol runs good, its female as well. If not, its a guy.
You see, when guys get mad at inanimate objects, we often call them a derogatory term normally reserved for females. When ladies get mat at inanimate object, they normally call them a derogatory term used for males. Ironically, they both start with "B."